Merge tag 'x86_misc_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 updates from Borislav Petkov:
 "The pile which we cannot find the proper topic for so we stick it in
  x86/misc:

   - Add support for decoding instructions which do MMIO accesses in
     order to use it in SEV and TDX guests

   - An include fix and reorg to allow for removing set_fs in UML later"

* tag 'x86_misc_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mtrr: Remove the mtrr_bp_init() stub
  x86/sev-es: Use insn_decode_mmio() for MMIO implementation
  x86/insn-eval: Introduce insn_decode_mmio()
  x86/insn-eval: Introduce insn_get_modrm_reg_ptr()
  x86/insn-eval: Handle insn_get_opcode() failure

1 files changed, 107 insertions, 2 deletions

diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index eb3ccffb9b9d..53e57ef5925c 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -37,8 +37,6 @@ enum reg_type {
  */
 static bool is_string_insn(struct insn *insn)
 {
-	insn_get_opcode(insn);
-
 	/* All string instructions have a 1-byte opcode. */
 	if (insn->opcode.nbytes != 1)
 		return false;
@@ -851,6 +849,26 @@ int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs)
 }
 
 /**
+ * insn_get_modrm_reg_ptr() - Obtain register pointer based on ModRM byte
+ * @insn:	Instruction containing the ModRM byte
+ * @regs:	Register values as seen when entering kernel mode
+ *
+ * Returns:
+ *
+ * The register indicated by the reg part of the ModRM byte.
+ * The register is obtained as a pointer within pt_regs.
+ */
+unsigned long *insn_get_modrm_reg_ptr(struct insn *insn, struct pt_regs *regs)
+{
+	int offset;
+
+	offset = insn_get_modrm_reg_off(insn, regs);
+	if (offset < 0)
+		return NULL;
+	return (void *)regs + offset;
+}
+
+/**
  * get_seg_base_limit() - obtain base address and limit of a segment
  * @insn:	Instruction. Must be valid.
  * @regs:	Register values as seen when entering kernel mode
@@ -1405,6 +1423,9 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
 	if (!insn || !regs)
 		return (void __user *)-1L;
 
+	if (insn_get_opcode(insn))
+		return (void __user *)-1L;
+
 	switch (insn->addr_bytes) {
 	case 2:
 		return get_addr_ref_16(insn, regs);
@@ -1539,3 +1560,87 @@ bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs,
 
 	return true;
 }
+
+/**
+ * insn_decode_mmio() - Decode a MMIO instruction
+ * @insn:	Structure to store decoded instruction
+ * @bytes:	Returns size of memory operand
+ *
+ * Decodes instruction that used for Memory-mapped I/O.
+ *
+ * Returns:
+ *
+ * Type of the instruction. Size of the memory operand is stored in
+ * @bytes. If decode failed, MMIO_DECODE_FAILED returned.
+ */
+enum mmio_type insn_decode_mmio(struct insn *insn, int *bytes)
+{
+	enum mmio_type type = MMIO_DECODE_FAILED;
+
+	*bytes = 0;
+
+	if (insn_get_opcode(insn))
+		return MMIO_DECODE_FAILED;
+
+	switch (insn->opcode.bytes[0]) {
+	case 0x88: /* MOV m8,r8 */
+		*bytes = 1;
+		fallthrough;
+	case 0x89: /* MOV m16/m32/m64, r16/m32/m64 */
+		if (!*bytes)
+			*bytes = insn->opnd_bytes;
+		type = MMIO_WRITE;
+		break;
+
+	case 0xc6: /* MOV m8, imm8 */
+		*bytes = 1;
+		fallthrough;
+	case 0xc7: /* MOV m16/m32/m64, imm16/imm32/imm64 */
+		if (!*bytes)
+			*bytes = insn->opnd_bytes;
+		type = MMIO_WRITE_IMM;
+		break;
+
+	case 0x8a: /* MOV r8, m8 */
+		*bytes = 1;
+		fallthrough;
+	case 0x8b: /* MOV r16/r32/r64, m16/m32/m64 */
+		if (!*bytes)
+			*bytes = insn->opnd_bytes;
+		type = MMIO_READ;
+		break;
+
+	case 0xa4: /* MOVS m8, m8 */
+		*bytes = 1;
+		fallthrough;
+	case 0xa5: /* MOVS m16/m32/m64, m16/m32/m64 */
+		if (!*bytes)
+			*bytes = insn->opnd_bytes;
+		type = MMIO_MOVS;
+		break;
+
+	case 0x0f: /* Two-byte instruction */
+		switch (insn->opcode.bytes[1]) {
+		case 0xb6: /* MOVZX r16/r32/r64, m8 */
+			*bytes = 1;
+			fallthrough;
+		case 0xb7: /* MOVZX r32/r64, m16 */
+			if (!*bytes)
+				*bytes = 2;
+			type = MMIO_READ_ZERO_EXTEND;
+			break;
+
+		case 0xbe: /* MOVSX r16/r32/r64, m8 */
+			*bytes = 1;
+			fallthrough;
+		case 0xbf: /* MOVSX r32/r64, m16 */
+			if (!*bytes)
+				*bytes = 2;
+			type = MMIO_READ_SIGN_EXTEND;
+			break;
+		}
+		break;
+	}
+
+	return type;
+}